EXTERNAL WALL INSULATION: The Defects are Often Built in. Part 2

The First Visual Signs of Premature Failure Explained

Underlying Rockwool Insulation Slabs Now Visible

Underlying Rockwool Insulation Slabs Now Visible

Some time back we blogged about a Midlands high rise EWI scheme that we’d monitored and noted that defects were being built in. Interestingly we have now noted very obvious visual signs of premature wall cladding failure. In fact we recently investigated a failed EWI scheme that exhibited a number of visual problems that were also noted on this scheme. When you consider that it generally costs circa £1m to install EWI to a high rise block then system failures become extremely expensive to remedy. In this particular case I drove past the building today and immediately noted early visual signs of system failure, in particular, what we call ‘thin coat failure.’ The white finished render should be ‘in plane’ and present a smooth finish across the whole facade but in this particular case you can now see that the underlying Rockwool insulation slabs in the Alsecco system are clearly visible; so what causes this and what are the implications?

Pillowing & Mattressing

We have previously written about the effects of pillowing and mattressing but this is something generally seen in Phenolic insulation boards, it isn’t a problem you see in Rockwool slabs.  Please read http://buildingdefectanalysis.co.uk/solid-wall-insulation-ewi/a-case-of-pillowing-or-mattressing/ for more information.

Technical Issues

Since we had initially commented that insufficient hammer fixings were being installed to the Rockwool slabs then we also believe that there is risk of structural failure at the interface between the Rockwool slab and the underlying substrate. However, experience tells us that the visual evidence suggest something far simpler… The render base coat has probably been applied far too thinly.  It is a problem that we are commonly seeing and we’re unsure if this is a result of the construction bean counters short ordering materials or whether it is simply down to poor site quality management?  The problem with overly thin render coats stretches well beyond the obvious aesthetic problem and raises two key technical issues.

  1. An overly thin render coat does not have the same impact resistance.
  2. An overly thin render coat is more permeable and hence far more susceptible to penetrating damp and subsequent saturation of the underlying insulation.
Another elevation with underlying Rockwool slab insulation clearly visible.

Another elevation with underlying Rockwool slab insulation clearly visible.

Thin Coat Failure

So we believe that this system is suffering from thin coat failure and has failed prematurely on both aesthetic and technical grounds and we predict significant technical problems in the near future. The only subjective discussion is with regard to the degree of failure exhibited.

You may wonder why these thin render coat failures are not immediately obvious on works completion and we think that is down to simple curing and shrinkage of the render, which can occur over a number of months; this project was only completed in October 2015 but visual system failures had to be evident months before we observed them. As the render coat shrinks back, it thins to reveal the underlying insulation boards, usually first noticeable when sunlight hits the elevation concerned.

Solution to Failure?

So, is there a remedy for this? If caught early enough before water penetrates and saturates the insulation, is there a quick fix? Sadly no. The problem is that whilst it may seem reasonable to offer additional coats to increase the render thickness, this  system would no longer have BBA approval. The reason for this is simple… You would be applying further base coat over an existing topcoat but the system was never tested with base coat applied over topcoat and therefore would no longer be BBA approved. We have written correspondence from the BBA stating precisely that fact.

Poor installation of Rockwool slabs.

Poor installation of Rockwool slabs.

It is easier to contextualise this system failure when comparing the underlying defects noted as the system was being installed and here we can see the poorly installed rectangular insulation slabs that are now showing through the render coat.

In our opinion both Rockwool slabs and EPS boards offer greater flexibility and potential for at least partial recovery of the EWI system but even retaining the insulation needs careful consideration based on a detailed investigation and recovery of site evidence.

 

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Building Defects: A legal perspective

Guest Blog Introduction and Biography

In March of this year both myself and Sarah Fox attended the RICS East Midlands CPD conference as guest speakers. I’d not met Sarah at this point and was lucky enough to attend her talk on letters of intent. Quite simply it was possibly the best talk on contract law that I’d ever attended and I was so impressed with Sarah’s knowledge of contract law that I asked if she’d write a guest blog.

Sarah Fox is a construction contracts strategist and author of a series of 500-word construction contracts. She wants the industry to adopt contracts that they can read, understand and use. She uses coaching, talks and workshops to help professionals to write simple contracts and understand complex ones. Her keynote is “Never sign on the dotted line” and you can find out more at http://www.500words.co.uk

Patent and Latent Defects

“Defects will occur in buildings. It is one of the great certainties in construction, the equivalent of death and taxes in life more generally” [1]

Borescope used to locate a latent defect.

Borescope used to locate a latent defect.

Generally a defect is “anything which renders the [works] unfit for the use for which it is intended, when used in a reasonable way and with reasonable care.” [2]

There are two types of defect: patent and latent. Patent defects are defects that are visible or capable of being discovered (observed and observable). Latent defects are not reasonably discoverable and often come to come to light after completion and even after the defects period.

Any client needs to ensure that the works meet the required contractual standards for goods, design and workmanship. This can be done in a number of phases:

During Construction

The contract administrator must identify visible defects and exercise her powers before completion and ensures that issues relating to quality and defects do not wait until the defects period. Depending on the terms of the building contract, the contract administrator may have:

  • the power to issue instructions to require the removal from site of work or materials not in accordance with the contract (JCT 2011 DB clause 3.13.1)[3] or other instructions as appropriate (JCT clause 3.14);
  • the power to require the contractor to open up or test various elements of the works (JCT clause 3.12);
  • a duty not to include in interim certificates the value of works not in accordance with the contract (JCT clause 4.14.1.1);
  • a right for the employer to terminate the contractor’s employment for failure to rectify defects as instructed, provided the works are materially affected (JCT clause 8.4.3);
  • the duty to confirm whether the works are completed to her satisfaction (MF/1 rev 5 clause 13.2);
  • the ability to confirm the performance of the works through testing before and after completion (MF/1 clauses 23, 28 and 35).

Obvious or ‘patent’ defects should prevent the issue of the certificate of completion. Accordingly, the date of completion, all work should conform to the requirements of the contract.

During Defects Period

Patent defect found on new development site.

Patent defect found on new development site.

Building contracts ‘encourage’ the contractor to return to the project and make defects right by allowing the employer to withhold some of the money due to the contractor until the end of the defects period, either a stage payment or retention. In Pearce & High v Baxter, the court said (with some reservations) that the JCT Minor Works wording “can be regarded as giving the contractor a right to make good defects at his own expense, and a licence to enter the property for that purpose.” [4]

After Defects Period

Once the defects period has come to an end, the client can bring a claim for breach of contract for any defects which become patent during the limitation period. The client’s claim is for damages to put it in the position it would have been in if the contractor had carried out the contract properly.

The difficulty is measuring what is an appropriate amount of damages.

 

Referencing

[1]           Article by Harrison Consult quoting Professor Anthony Lavers.

[2]                 Yarmouth v France (1887) 19 QBD 647. See also Tate v Latham [1987] 1 QB 502 where a defect meant the absence of an item essential to complete the works – even if the works were operable without the item.

[3]           There is no power for the contract administrator to instruct when these defects must be rectified as it is for the contractor to plan and perform the works however it chooses. All references in this blog are to JCT 2011 DB unless otherwise noted.

[4]                 [1999] CLC 749 at 751.

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Damp in Old & Historic Buildings

Managing damp problems in old buildings

CPD Session in Nottingham

There will be an opportunity to attend a talk I’ll be giving in dealing with damp in old and historic buildings on the 19th of May in Sandiacre, Nottingham. Full details can be found on the following link

The event is being organised by Jane Newton at the CIOB, whose contact details can also be found in the link above. The event is £5 to non-members of the CIOB and free to members and students. Whether you are a practising surveyor or just have an interest in old buildings then I’m sure you’ll find it fascinating.

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The talk should last about an hour with a Q&A afterwards. Topics that I’ll be covering are:

1. Tools of the Trade
2. The principles of moisture management
3. Back to basics: A focus on critical technical details.
4. Understanding moisture equilibrium
5. Cure or management solution
6. The holistic damp investigation process
7. A brief update on rising damp
8. Condensation damp & ventilation strategy.

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Guarantees for Solid Wall Insulation and Getting Insurance for Failure.

More Unscrupulous Dealings from The World of External Wall Insulation

If considering EWI then accept nothing less than a 25 year guarantee. Some unscrupulous installers will not offer it.

If considering EWI then accept nothing less than a 25 year guarantee. Some unscrupulous installers will not offer it.

We have previously warned about the double standards being operated by some external wall insulation installers with regard to the guarantees being offered on these systems. DECC insisted that these systems came with a 25 year guarantee if they were to be rolled out to the mass market; enter SWIGA, the company formed to provide those guarantees. However, it seems that a large proportion of the industry is only providing those guarantees for grant funded work, such as ECO funding. If you are a cash buyer for one of these systems then there is a strong chance that you will be offered a substantially reduced guarantee. I have a client who was only offered a 12 month guarantee, though their installer later offered to pass on the system manufacturers 5 year materials guarantee, which is fairly pointless. When made aware of the 25 year SWIGA guarantee my client questioned this but found that their installer was not a member of SWIGA and therefore could not offer the 25 year guarantee. As grant funded work dries up we are seeing a number of installers sever ties with SWIGA or generally failing to maintain any links with a body that can provide the appropriate level of insurance protection. After all, if the Government isn’t forcing you to offer a 25 year guarantee then why pay membership to an organisation that oversee’s an insurance scheme that you are not offering to clients. Irrespective of whether work is privately or grant defended this application of double standards is an industry scandal. In this particular case the installer was recommended to my client by the system manufacturer, despite that installer having no way to provide the appropriate guarantee. Should we expect material suppliers to carry out some level of due diligence to ensure that their recommended installers can offer an appropriate guarantee? I think so, and if you can’t do this then don’t make recommendations!

 If you have followed this blog then you will be aware that the system failed within weeks of being applied leading to months of conflict and disagreement. One culmination of the disagreement over the guarantee being offered, or rather, not being offered, was the installers suggestion that they would now provide the following system guarantee…

Screen Shot 2016-04-06 at 21.20.35

 

To my mind this raised a very obvious question, which is, can you actually get insurance cover for an EWI system that has already failed? Possibly… but as with all things risk related, the greater the risk, the more you pay to offset that risk. In this case we are fairly confident that the insurance company  would refuse to insure a previously failed and repaired system, or they would increase the premium to such an extent that the installer would not want to pay the price. We are fairly confident that the system failure was not disclosed to the insurer because the insurer would have wanted to know the full facts relating to the cause of failure and repair in order to help their loss adjusters reach a decision. So in fact a guarantee is being offered when the insurer is not yet in receipt of all the facts relating to the case. We’d go so far as to say that having spoken to this insurer, the policy may not actually be available under these circumstances. It goes without saying that it would be construed as fraud to obtain an insurance policy without disclosing all material and relevant facts and I’d consider substantial failure of the system within weeks of application as fairly relevant, wouldn’t you? You can pick holes in a lot of these policies until the cows come home and the fact remains that the vast majority of EWI failures are caused by poor workmanship, inadequate design or poor site storage of materials. Given that poor workmanship is the primary common cause of failure then you’re left in dispute with your contractor because a lot of these policies only pay out in those circumstances if your contractor is no longer around to deal with it. There are a lot of aftermarket guarantees and you should study them carefully if you’re placed in an unfortunate  position of having to buy one. To avoid this proverbial stable door simply ensure that your installer is registered with SWIGA and can provide the full 25 year protection; If not then find an installer who can! Oh, and please budget to have your installation independently quality managed, we guarantee that you’ll be glad you did.

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